Complete inhibition of localized corrosion in 5Cr steel under a water-saturated supercritical CO2 environment through Al microalloying

Abstract

To address the critical corrosion challenges faced by metal pipelines in carbon capture, utilization, and storage (CCUS) technologies, the study prepared a series of novel Fe-5Cr-(0–3)Al alloy steels. The corrosion resistance of these alloys in a water-saturated supercritical CO₂ (sc-CO₂) environment was systematically investigated. The results revealed that increasing Al content significantly reduced the corrosion rate. When the Al content reached 2 wt%, the average corrosion rate decreased by 68% of that of conventional 5Cr steel, and localized corrosion was completely suppressed. Furthermore, the study explores the underlying mechanisms of localized corrosion, shedding light on the key factors contributing to this remarkable performance. These findings not only demonstrate the alloys' potential as a cost-effective, high-performance solution for CCUS applications but also provide a scientific foundation and technical guidance for the development of future corrosion-resistant steels.